Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-25122

CVE-2021-25122HIGH

Apache Tomcat h2c request mix-up

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  N  N    7.5   .1811   97.2     —

AFFECTED
  Product        Versions            Fixed
  Apache Tomcat  Apache Tomcat 10 –  —

TIMELINE
  Jan 14  Reserved by apache
  Mar 1   Published (CNA: apache)
  Oct 8   ENRICHED — CVE-2021-25122 (Apache Software Foundation Apache Tomcat). Received CVSS 7.5 and CPE data from NVD.

CWE-200 · CNA: apache · CVSS v3.1 · 15 references · NVD status: Modified

Description

When responding to new h2c connection requests, Apache Tomcat versions 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41 and 8.5.0 to 8.5.61 could duplicate request headers and a limited amount of request body from one request to another meaning user A and user B could both see the results of user A's request.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
January 14, 2021	Reserved	Reserved by apache
March 1, 2021	Published	Published (CNA: apache)
October 8, 2026	ENRICHED	ENRICHED — CVE-2021-25122 (Apache Software Foundation Apache Tomcat). Received CVSS 7.5 and CPE data from NVD.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Apache Software Foundation	Apache Tomcat	—	Apache Tomcat 10	—

Weaknesses

CWE-200

References (15)

http://www.openwall.com/lists/oss-security/2021/03/01/1 [Mailing List, Third Party Advisory]
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.apache.org%3E
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apache.org%3E [Mailing List, Vendor Advisory]
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cdev.tomcat.apache.org%3E
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cusers.tomcat.apache.org%3E
https://lists.apache.org/thread.html/rcd90bf36b1877e1310b87ecd14ed7bbb15da52b297efd9f0e7253a3b%40%3Cusers.tomcat.apache.org%3E
https://lists.apache.org/thread.html/rd0463f9a5cbc02a485404c4b990f0da452e5ac5c237808edba11c947%40%3Cusers.tomcat.apache.org%3E
https://lists.apache.org/thread.html/rf6d5d57b114678d8898005faef31e9fd6d7c981fcc4ccfc3bc272fc9%40%3Cdev.tomcat.apache.org%3E
https://lists.debian.org/debian-lts-announce/2021/03/msg00018.html [Mailing List, Third Party Advisory]
https://security.gentoo.org/glsa/202208-34 [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20210409-0002/ [Third Party Advisory]
https://www.debian.org/security/2021/dsa-4891 [Third Party Advisory]
https://www.oracle.com//security-alerts/cpujul2021.html [Patch, Third Party Advisory]
https://www.oracle.com/security-alerts/cpujan2022.html [Patch, Third Party Advisory]
https://www.oracle.com/security-alerts/cpuoct2021.html [Patch, Third Party Advisory]

Authoritative record: CVE-2021-25122 at cve.org

Vendors: apache

Weaknesses: CWE-200

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-25122 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.